Re: How many postcards/letters makes a mass mailing
I don't know what it is in this industry but in sales, 1% is the typical Return on Investment (ROI). I think the key is to target an area, maybe 1000 or so, and market to the same people about every three months. It's all about name recognition and even though some may not need your services now they may in the future. You need to keep your name in front of them.
Also including some kind of special price may help.